(a) Field of the Invention
This invention relates to a mechanical drive system for driving a two-wheel, pedal powered vehicle and more particularly, but not by way of limitation, to a linear to rotary transfer drive system, using pedal power, for increasing the torque input on a bicycle or similar chain, cable or belt driven vehicle.
(b) Discussion of Prior Art
Heretofore, a rear wheel of a standard single speed, three speed, ten speed or other speed, two-wheel or three-wheel bicycle must be continuously rotated by a bike rider using a pair of pedals mounted on a rotary drive axle with rotary drive sprocket and horizontal endless chain. The rotary drive axle is mounted on a bicycle frame with a seat, a front wheel used for steering, and the rear wheel connected to the endless chain for driving the bicycle.
The standard rotary drive chain system for the bicycle using a pair of pedals provides for only ½ of the torque, in pound/feet, for rotating the rear wheel when compared to a linear drive chain system, which provides full torque thereon. For example, when moving a first pedal on the right side of a bike frame in the standard rotary drive system from a 12 o'clock position to a 3 o'clock position on the drive axle and drive sprocket, variable torque is applied from zero to maximum. But, the torque dissipates from maximum to zero when moving from the 3 o'clock position to the 6 o'clock position. At the same time, a second pedal on the left side of the bike frame moves from a 6 o'clock position to the 12 o'clock position and provides no torque on the drive axle and drive sprocket unless the second pedal is fitted to exert a lifting force, which would provide torque from zero to maximum a 9:00 o'clock then back to zero at 12:00 o'clock.
The subject linear to rotary drive system provides for full torque on the drive shaft and drive sprocket during any linear movement of the bicycle's two pedals. For example, if the standard rotary drive system on the bicycle delivers 1 pound/foot of torque rotating the bike pedals a full cycle, the subject linear drive system attached to the rotary drive system delivers 2 pound/foot or twice the amount of torque, when moving the bike pedals a full cycle up and down.
In U.S. Pat. No. 556,802 to Boyle, a different linear to rotary chain driven bicycle is disclosed. The Boyle bicycle includes one modified, rotary drive chain attached to the drive sprocket activated by the down motion of one of the bike's pedals. Also, the bike system includes a second chain which activates the drive sprocket via a down force of a second bike pedal. The pedals include pawls for lowering the chains from an up position to a down position. Further, the bike system includes a third transverse chain for raising the pedal opposite to the pedal being lowered. This prior art patent doesn't disclose a near vertical, endless linear drive sprocket chain mounted on a pair of linear drive sprockets independent of the bike's rotary drive sprocket and the endless rotary drive chain. Also, this patent doesn't disclose pedals that can provide increased torque on the rotary drive axle and the rotary drive sprocket during both the up and down linear movement of the two pedals.